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Food fight

Caught in the maize at Berkeley. Published in  California Monthly magazine.

It all began with a single cob of corn. Picked in a remote part of Oaxaca, Mexico, this seemingly innocent vegetable made its way into a lab in Berkeley. From there, it sparked a food fight on a global scale. Accusations were hurled back and forth of “bad science,” “McCarthyism,” and “conflicts of interest,” creating a mess of science, politics, ethics, international trade, and global ecology.

That contentious cob of corn, a local Mexican varietal, was brought to Berkeley by graduate student David Quist. When Quist analyzed the kernels in his lab, to his surprise he found traces of DNA from genetically engineered corn, the planting of which has been banned in Mexico since 1998. This indicated that transgenic corn was growing illegally in Mexico, and that it was crossing with the local corn varieties.

Quist and his adviser, assistant professor Ignacio Chapela, spent the next several months confirming this result, and in November of last year published a paper in the peer-reviewed science journal Nature. Their findings were important and troubling, says Chapela, because these transgenes might eventually infiltrate every native variety in Mexico, thus reducing the genetic diversity of maize. Corn originated in Mexico, which remains the center of genetic diversity of the crop; threats to local varieties would also threaten our future food security, says Chapela.

In their paper, Quist and Chapela also presented evidence that the transgenes themselves, once they move into local varieties, become unstable, splitting apart and scattering throughout the genome. If correct, this would mean that the effects of these renegade genes in the wild would be unpredictable and potentially hazardous.

Immediately following publication of theNature article, environmental groups including Greenpeace called for an immediate ban on the import to Mexico of transgenic corn from the U.S., the presumed source of the “contamination.” But, almost as quickly, some plant biologists began to take issue with the Quist and Chapela paper, saying that the science was wrong, despite the fact that Nature uses independent scientists to check for errors before publication. Critics called on the journal to retract the paper.

And so the “Mexican maize scandal,” as Science magazine has called it, was born. Petitions were circulated, each side accusing the other of conflicts of interest. Environmental groups charged that there was a McCarthyist campaign led by the plant biotechnology industry to silence Quist and Chapela and their work. Scientists supportive of transgenic research dismissed the two Berkeley researchers as “activists” rather than scientists, and claimed that their research was driven by politics alone.

“They have nothing there, except preconceptions,” charges Michael Freeling, a professor in the Department of Plant and Microbial Biology (PMB) who signed a petition calling for a retraction of the Nature paper. “It’s just politically motivated.” Chapela counters: “Behind their superficial technical criticism lies a very deep and very strong political campaign.”


Then, in April, things really blew up. Nature published two critiques of the original paper, plus a response from Quist and Chapela. One of those critiques was written by Nick Kaplinsky, a graduate student of Michael Freeling’s, who, along with others (pictured below), also signed the petition against the original paper.

But the real spark in the powder keg was a note from the editor which said: “Nature has concluded that the evidence available is not sufficient to justify the publication of the original paper.” It is believed to be the first time in its 133-year history that the journal has done such a thing.

Chapela’s supporters claimed that Nature‘s unprecedented move was proof of a campaign to discredit him. They alleged that Nature‘s withdrawal of support was timed to influence a meeting in The Hague in which the world’s environment ministers were to discuss the very issue of transgenic crops in centers of genetic diversity. Biotechnology companies, they said, didn’t want Chapela’s findings getting in the way of lifting the Mexican moratorium on the planting of transgenic crops or other restrictions elsewhere.

Some suggested another plot–a local campaign to force Chapela out of Berkeley. Professor Miguel Altieri, a colleague of Chapela’s, suggests that the critiques had been timed to come out just before Chapela’s tenure review this spring. Altieri points out that many in the Department of Plant and Microbial Biology had a bone to pick with Chapela, who has been an outspoken critic of the deal signed by their department in 1999 with the biotech company Novartis (now Syngenta). “Now it’s time for payback,” says Altieri.

But Kaplinsky is adamant that his critique had no connection with the Novartis deal, and points out that he personally does not receive money from Novartis. “It had nothing to do with that at all. Here was a paper in our field of expertise [maize genetics] that was making some pretty wild claims,” says Kaplinsky. “Clearly, there is history here. But I really think if I ever see science this bad published again, especially inNature, I’d write a letter about it.”

Quist and Chapela identified the transgenic elements using a technique called inverse PCR (iPCR), which Kaplinsky argues is prone to false positives. “It was really sloppy science. No self-respecting scientist would take that approach because it gives you meaningless results,” he says. Kaplinsky argues that the DNA sequences identified in the paper as “transgenic” are nothing more than artifacts. Quist counters that he took those issues into account in designing his experiments. “That’s why we spent so much time and used rigorous controls-to be able to say those aren’t false positives,” he says.

Chapela believes that the published critiques themselves show evidence of something other than just “healthy scientific debate.” He notes that criticism focused not on their main finding–that native corn has been crossing with transgenic corn–but only on their secondary conclusion-that transgenes break apart and scatter upon entering a new genome. “Of the eight [DNA] sequences that we published, two sequences were challenged, and we agreed that the critics’ interpretation of these sequences is better,” says Chapela, who adds that iPCR is still an exploratory technique whose results are open to interpretation. “But then they go on to say that all eight sequences are wrong–not misinterpreted but wrong–and that therefore our methodology is wrong, the lab is badly run, and our primary statement is also wrong.” 

Although he is reluctant to believe that his colleagues at PMB have been plotting to get rid of him, Chapela does think that Novartis has had an influence on the course of events. He notes that the second critique in Nature was written by a former PMB graduate student, Matthew Metz, a vocal supporter of the Berkeley-Novartis deal. “People have viewed it as a local vendetta against me and David [Quist], but I think that’s myopic. I believe somebody used the tension that existed here, because of the Berkeley-Novartis deal, for a much larger political purpose.”


Yet, in spite of the accusations, the name-calling, and the distrust, everyone seems to agree on one thing-that transgenic corn is growing in Mexico and that it is most likely crossing with local varieties. “It’s obvious that there’s transgenic corn in Mexico,” says Kaplinsky. “But there’s a difference between saying something is obvious and proving it scientifically.”

What they can’t agree on is whether this crossing is a good or bad thing. Chapela believes that it will lead to ecological problems. And, in any case, he adds, whether others agree with him on this point or not, international treaties were put in place to prevent such crossing. “We were assured that this [crossing] would never happen,” he says. “For me, the most important question is: Can we maintain and increase the diversity of germplasm available in these areas? We depend on such diversity.”

Kaplinsky and Freeling are not so sure that the diversity of maize is threatened by transgenes. They even signed a statement saying that “the kind of gene flow alleged in the Nature paper is both inevitable and welcome.” Introducing new traits would increase the diversity of the maize, they say. Nevertheless, for Freeling, this is not the most important question. “When you publish bad science and then don’t step up and own it, retract it, and apologize, some disrespect is to be expected. That’s more important to us than the GMO issue,” he says.

At the root of all these disagreements there appears to be a fundamental disagreement about the nature of science. “They are very interested in talking about politics, but I am much more interested in talking about science,” says Kaplinsky. But Altieri believes there is no way of talking about one without talking about the other: “Scientific questions are also political questions. There is no such thing as neutral science because every scientist is influenced by their value system and their history.” Such differences suggest that we may not see any reconciliation between the two groups any time soon.

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